Window envelope



June 24, 1930. w. T. voN wlNKLER 'i 1,766,416

WINDOW ENVELOPE Filed Aug. 2'7. 1928 Patented ,lune 24, 1930 awe-,41e

',WALTER T. VON WINKLER, CHICAGO DREDTHS TO VON WINKLER CHEMICAL CO., AFIVE ONE-HUNDREDTHS TO SAMUEL W. WEIS ILLINOIS, ASSIGNOR OF TEN ONE-HUN-AN D EORTY-FIVE ONE-HUNDREDTHS TO MARINO GENTILE, ALL OF'CHICAGO,ILLINOIS WINDOW ENVELOPE Application led August 27, 1928. Serial No.302,314.

Thisinvention relates to mailing envelopes of the type commonly known asWindow envelopes, wherein the face of the envelope is provided with atransparent portion or window which renders visible Vtherethrough thename and address written or printed on the enclosure.

Window envelopes of this type now in use have, for the most part, beenmanufactured in one of twoways. In one way, oil is appliedto the surfaceof the paper and allowed to dry, thus rendering the paper sufficientlytransparent to enable the name and address to be visible therethrough.According to the other method, an oblong slot is cut in the face of theenvelope and a piece of so-called glassine paper, which is transparent,is pasted to the underside of the front wall of the envelope over saidopening. In envelopes rendered transparent by the use of oil, the frontand rear surfaces of the front wall of the envelope are, of course,perfectly smooth, but the visibility is considerably below that alfordby the glassine paper strip or window. Oli

the other hand, a strip of glassine paper pasted to the rear wall of theenvelope occasionally becomes loosened or detached at its edges, andpresents an obstruction to the insertion of the enclosure and issometimes torn by the latter.

An object of the present invention is to provide an dirnpyed windowenvelope wlcl'wll possess perfect transparency and visibility withentire freedom from tlefaults above-noted.

Again, window envelopes, to be commercially practical, must be capableof being man,- ufactured in large quantities economically and by highspeed operation-s; and another 40 object of the present invention is toprovide a window envelope which can be Vroduced under the conditions`last specified). v

A still further object of the invention is to provide a window envelopeof the transparent strip type wherein the transparent strip will besecurely held in place and will be free from any liability ofdisplacement or breakage by the enclosure when the latter is inserted inthe envelope.

Other objects and attendant advantages of the invention will be apparentto persons skilled in the art as the same becomes better understood byreference to the following detail description, taken in connection withthe accompanying drawing, in which I have illustrated a simple andpractical embodiment of the principle of the invention, and wherein-Fig. 1 is a front elevation of the improved envelope;

Fig. 2 is a cross-section, enlarged, on the line 2-2 of Fig. 1.

Referring to the drawing, 10 may designate the envelope as an entirety,of the usual rectangular form, 11 being the front wall thereof and 12and 13 representing the usual lower and upper liaps respectively on therear side of the envelope.

vIn the front wall 11 is cut the usual oblong opening 14, and formingthewindowof this opening is a transparent Hlm 15 of less thickness thanthe wall of the envelope and greater width and length than the opening14, and having the portions thereof lying beyond the edges of theopening 14 embedded in and completely covered by the paper stock of thefront wall. This transparent lilmmay be of anynsuitablematerial, such asglassine pa CORPORATION OF ILLINOIS, IEORTY- per, gelatine,lnitro-cellulose or cellulose-acetate,-prefe'ralolyv nitro-cellulose orcelluoseacetate on account of the perfect transparency andmoisture-proof qualty of these substances. One practical method ofmanufacturing the envelope may be brieiy described as follows. `A pairof continuous thin unfinished paper webs, as they come from the y.web-forming vat of a papermaking machine, and each of a width equal toor greater than that of the envelope blank, with the open ings 14 outtherein, and, if desired, transversely perforated or scored at spacesequal to the length of an envelope blank, may be advanced at equalspeeds from delivery reels or directly from a pair of paper makingmachines toward each other so that their openings 14 will exactlyregister, and simultaneously a transparent strip of a width slightlygreater than suffices to span the width of the openings 14 andpreferably perforated or scored to register with the perforated orscored lines of the paper webs is advanced at the same speed between thelatter, and the three webs then travel between compression andcalendering rollers which press t e fibres of the unfinished paper websinto felted and interlocked association with each other, therebyproducing a single integral finished sheet with the transparent filmbodily incorporated therein. If desired, the unfinished webs beforereaching the point of compression may travel over a pair of sizing rollswhich will apply a thin film of size to their inner adjacent surfaces,and as the sized unfinished webs are squeezed together the film of pasteapplied thereto is distributed by pressure throughout the fibres ofbothwebs'. In such a case, the portions of the transparent film that areincorporated in the paper sheet are adhered to the fibrous stock of thelatter. However, if the unfinished webs or films, whether of sized orunsized fiber, are not too dry, the pasting or sizing of theircontiguous surfaces may be dispensed with, the heavy pressure underwhich they are squeezed together sufiicing tothoroughly felt togetherand integrate the webs and securely embed the transparent film therein.

The continuous strip thus formed may then be divided on the perforatedor scored lines, and the separated sheets then subjected to filmoccupying said opening and having margmal portlons thereof embedded inthe portions of said wall bounding said opening.

2. A window envelope having its front wall consisting of a singleintegral sheet and formed with an opening, and a transparent film ofless thickness than said front wall and of greater width and length thansaid wopening occupying the latter`with the marginal portions thereoflying beyond the edges of said opening embedded in and covered by thestock of said front Wall.

WALTER T. VON WINKLER.

the usual blank cutting, folding, pasting and gumming operations toproduce the completed envelope.

In the drawings per and the transparent film relatively to thedimensions of the envelope are necessarily much exaggerated.

The above described envelope possesses the advantages that the windowclosure `lies wholly between the planes of the front and yrear surfacesof the front wall of the envelope, has no exposed edges to break or tearaway from the wall of the envelope, and is very strongly and securelyheld in place.

While I have herein shown and described a useful and practicalembodiment of the in-` vention, I do not limit the latter to theparticular form and construction herein presented, but reserve all suchvariations and modifications as fall within the spirit and purview ofthe claims.

I claim- 1. A window envelope having a wall thereof consisting of asingle integral sheet and formed with an opening, and a transparent thethicknesses of the pa-

